In the field of building and construction, concrete walls, concrete floors, and concrete roofs are often formed by molding poured concrete using insulating forms. Insulating wall forms typically comprise a pair of spaced, vertical panels that define a volume into which liquid concrete is poured and allowed to set. The insulating wall forms may be removed once the concrete has set, or alternatively may be left in place.
Insulating wall forms have been previously described. For example, U.S. Pat. No. 6,536,172 to Amend discloses an insulating construction form consisting of a pair of spaced apart panels and a plurality of ties. Tie members include pairs of resilient retainer arms, which define a series of adjacent receptacles. A reinforcing bar is typically inserted into the receptacles, and its displacement therefrom is inhibited by abutment surfaces. Markings are positioned on each panel to guide the attachment of a cladding.
Insulating wall forms used to form wall sections having a corner typically comprise an inner panel and an outer panel, where each of the panels has a respective panel corner, and where the panels are spaced to define a volume into which liquid concrete is poured and allowed to set. However, certain challenges arise during use of conventional insulating corner wall forms. For example, when liquid concrete is poured into the form, the liquid concrete flows in a direction that is perpendicular to a concrete-facing surface of the outer panel in the region of the corner. As will be appreciated, the weight of the flowing concrete exerts a significant impact force on this concrete-facing surface of the outer panel, and can continue to exert force on the outer panel as it makes its way around the corner. These forces can cause the outer panel to bulge outwardly, shift and/or blow out (that is to crack and break into pieces), causing the form to fail.
Internal ties for providing rigidity to insulating corner wall forms are known. For example, U.S. Pat. No. 7,861,479 to Crosby et al. discloses a form for poured concrete walls having a corner bracket that includes an outer, horizontal strap with generally vertical strips attached thereto or molded therewith for encapsulation in the outside, and optionally the inside, foam panels of the form.
U.S. Patent Application Publication No. 2008/0155925 to Pfeiffer discloses a corner bracket member for use in an insulated concrete form corner block or other form assembly having a pair of opposed inner and outer spaced apart panels for receiving concrete therebetween. The corner bracket member includes at least a pair of side members, each side member having at least a pair of spaced apart flange members adapted for receiving and anchoring exterior facade or other surfaces thereto, and at least one concrete engaging member positioned and located so as to extend in a direction completely across the space formed by and between the inner and outer panels associated with the insulated concrete form corner block. The side members and flange members of the corner bracket member are encapsulated within one of the inner and outer panels, and the at least one concrete engaging member includes a terminal end portion which is encapsulated within the other of the inner and outer panels when attached thereto.
U.S. Patent Application Publication No. 2007/0175155 to Cymbala et al. discloses a form for use in a concrete wall forming system to define wall sections meeting an intersection region. The form comprises panels arranged in a spaced relationship to each other to define therebetween a volume for each wall section and an intersection volume for the intersection region, and a series of ties forming a stack of ties. Each tie has an exterior frame having at least three sides, corners where two adjacent sides meet and a web member spanning generally across an interior volume within the frame. Each tie is located in the intersection region with two sides spanning between opposing sides of opposing panels and has each corner embedded within a panel.
U.S. Patent Application Publication No. 2009/0308011 to Philippe discloses an insulated concrete form panel reinforcement. The insulated concrete form comprises a main panel, a reinforcement on the main panel for stiffening the main panel, a spacer retention element integrated in the reinforcement for securing a spacer to the panel, and a first opposing panel opposite the main panel and having a first opposing spacer retention element integrated therein for securing the spacer to the first opposing panel. The insulated concrete form panel reinforcement is particularly useful at high stress locations, such as at T-wall intersections.
Deficiencies of prior art insulating corner wall forms comprising internal ties are known. For example, FIG. 1A shows a prior art insulating corner wall form, which is generally indicated by reference numeral 20. Form 20 comprises an inner panel 22 and an outer panel 24. Each of the panels 22 and 24 is fabricated of molded foam, such as for example of expanded polystyrene (EPS). The inner panel 22 is spaced from the outer panel 24 so as to provide a fixed space, or a volume 26, therebetween for receiving a charge of poured concrete (not shown). The form 210 also comprises a plurality of longitudinal ties 32 connecting the inner panel 22 and the outer panel 24, and which span the fixed space. Each tie 32 is terminated by a pair of flanged ends 36, with each flanged end 36 being embedded within a respective one of the inner panel 22 and the outer panel 24 during molding of that panel. The form 20 further comprises an internal corner bracket 38 that is integral with the outer panel 24, and which has a corner tie 42 connected thereto and extending therefrom. The corner tie 42 is terminated by a flanged distal end 44 that is embedded within the inner panel 22.
In use, when concrete is poured into the volume 26 of the form 20, the corner tie 42 provides resistance to bulging of the outer panel 24 away from the inner panel 22 under forces associated with the weight of the concrete. However, as will be understood, the large area of each concrete-facing surface of the outer panel 24 between the corner tie 42 and each adjacent tie 32 renders the outer panel 24 susceptible to rupture or breaking. In the event of a break, the broken corner piece, now otherwise disconnected from the outer panel 24, can pivot about the single attachment point of the corner tie 42 at the inner panel 22, causing the form 20 to fail.
FIG. 1B shows another prior art insulating corner wall form, which is generally indicated by reference numeral 60. Form 60 comprises an inner panel 62 and an outer panel 64. Each of the panels 62 and 64 is fabricated of molded foam, such as for example of expanded polystyrene (EPS). The inner panel 62 is spaced from the outer panel 64 so as to provide a fixed space, or a volume 66, therebetween for receiving a charge of poured concrete (not shown). The form 60 also comprises a plurality of longitudinal ties 72 connecting the inner panel 62 and the outer panel 64, and which span the volume 66. Each tie 32 is terminated by a pair of flanged ends (not shown), with each flanged end being embedded within a respective one of the inner panel 62 and the outer panel 64 during molding of that panel. The form 60 further comprises a webbed corner tie 80 comprising a center tie 82 and two (2) peripheral ties 84, with each peripheral tie 84 being adjacent the center tie 82. The corner tie 80 has a flanged connector (not shown) that is embedded within the inner panel 62, and each of the center tie 82 and the peripheral ties 84 is terminated by a flanged distal end (not shown) that is embedded within the outer panel 64.
In use, when concrete is poured into the volume 66 of the form 60, the corner tie 80 provides resistance to bulging of the outer panel 64 away from the inner panel 62 under forces associated with the weight of the concrete. However, as the peripheral ties 84 are spaced from the center tie 82 on the concrete-facing surface of the outer panel 64 by a distance that generally corresponds to the distance spanned by each tie 72, there exist two large unreinforced regions on the concrete-facing surface of the outer panel 64. These large unreinforced regions bear a great deal of the force from the weight of poured concrete flowing through the volume 66, because they are directly in-line with the flow of poured concrete. As a result, the outer panel 64 at these unreinforced regions is greatly susceptible to cracking or breaking during concrete pouring. In the event of a break, the broken corner piece, now otherwise disconnected from the outer panel 64, can pivot about the single attachment point of the corner tie 80 at the inner panel 62, causing the form 60 to fail.
Improvements are generally desired. It is therefore an object of the present invention at least to provide a novel insulating corner wall form.